Using Events to Identify Users Across Channels

Some Dynamic Yield standard events also serve to associate a given user ID (DYID) with a unique customer ID (CUID). A user ID is unique to a device or browser and might represent an anonymous user. It's the primary identifier in API endpoints. The optional CUID is a fixed identifier for a person that's the same across channels (web, mobile apps, email) and is usually assigned only to registered users. It enables linking the user's event history, affinity, and audiences across multiple devices and channels.

The CUID can be any unique string. However, we recommend using the customer's email address as the unique identifier, to support email personalization features. Pass email addresses in hashed SHA256 format. While optional in some events, this ensures consistency between all identifying events for the same user reported from multiple sources, and with any first-party data you upload. Note that hashed email addresses are further encrypted when stored on our servers.

Dynamic Yield does not generally mandate that you pass a CUID, but it is required in Login and Identify User events. Without it, the event reports a login that might be a primary metric for a campaign, but does not tie the user ID to any CUID.